1. Field of the Invention
The present invention relates to a non-halogen flame retardant and high rigidity polycarbonate resin composition, and more particularly, to a non-halogen flame retardant and high rigidity polycarbonate resin composition having flame retardancy with rigidity overcome a poor rigidity as a conventional problem occurred, upon adding a flame retardant agent in polycarbonate resin composition reinforced with a glass fiber having improved rigidity such as flexibility and surface smoothness etc., imposed by the use of the glass fiber.
2. Description of the Related Art
Among thermoplastic resins, polycarbonate resins have been widely used as an engineering plastic material due to their high impact resistance, excellent electrical properties, high moldability, stable physical properties in a wide temperature range, and self-extinguishing properties.
Since polycarbonate has various uses and is applied to a variety of electrical and electronic appliances generating a large amount heat, polycarbonate needs to be reinforced with a flame retardant to improve flame retardancy.
When various known brominated and chlorinated flame retardants burn, highly toxic gas is produced. Due to human toxicity thereof, legal restrictions on products thereof increase. In addition, impurities and by-products produced from the brominated and chlorinated flame retardants may corrode equipment for manufacturing and using polycarbonate.
In recent years, as thin film techniques are applied to electrical and electronic appliances, glass fiber-reinforced polycarbonate resins have been used. Since tensile/flexural strength, tensile/flexural modulus, and heat resistance are generally improved when polycarbonate resins are reinforced with a glass fiber, the glass fiber-reinforced polycarbonate resins may be suitable for products under continuous load at high temperature. However, fluidity is rapidly reduced in glass fiber-reinforced polycarbonate resins. Accordingly, surface roughness of a molded article may be increased as the glass fiber protrudes from the surface of the molded article during a molding process, and rigidity such as impact strength and tensile elongation is considerably reduced, thereby being vulnerable to external impact. Thus, there are limitations on use glass fiber-reinforced polycarbonate resins in housings of electrical and electronic appliances.
When polycarbonate having a low molecular weight is used in order to overcome these problems, moldability is improved, but impact resistance and chemical resistance are rapidly deteriorated. When a general impact modifier having a core-shell structure is added thereto, fluidity decreases, sufficient impact resistance cannot be obtained due to destruction of the glass fiber and deterioration of the resin caused by excess shear stress and surface roughness may increase due to protrusion of the glass fiber from the surface.
Korean Patent Application Publication No. 2009-0052447 discloses a glass fiber-reinforced polycarbonate resin composition including 50 to 90% by weight of polycarbonate, to 40% of a glass fiber, 1 to 10% of a thermoplastic elastomer polymer, 1 to 10% of an impact modifier with a core-shell structure, and 1 to 10% of an ethylene acrylate resin. In this case, in molding of a thin product having a complex structure, shrinkage difference occurs due to the glass fiber reinforcement between a flow direction of the glass fiber and a direction perpendicular to the flow direction, thereby causing product deformation.
In order to prevent deformation caused during a molding process, a laminar impact modifier such as talc, mica, and glass flake may be added thereto. However, in this case, efficient rigidity cannot be obtained in comparison with the added amount. In weld lines, physical properties are rapidly deteriorated at weld lines, and thus the composition cannot be applied to products having a lot of weld lines.
Therefore, there is a need to develop a glass fiber-reinforced flame retardant polycarbonate resin composition that has excellent flame retardant, no distortion (warpage) of the product after molding, no surface protruding of the glass fibers, and high impact resistant.